In this specification where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.
Near-infrared (NIR) fluorescent dyes have received attention in recent years. However, despite the advantages of polymers and their use in the NIR range, the currently available NIR dyes are all small molecules with a single reactive site. NIR polymers, especially water-soluble NIR polymers with multiple reactive sites and low band gaps are still lacking. Water solubility is a beneficial property for dyes to be used in many applications. The use of NIR polymers for such applications has been hampered by lack of water solubility.
A conventional method of making molecules water-soluble is to introduce charges to their molecular structures. Introduction of charges significantly enhances water solubility of molecules, like all the commercially available water-soluble dyes which are charged molecules. However, the presence of charges in molecules could cause potential interfering responses due to non-specific electrostatic interactions in complicated biological samples.
Thus, there is a need in the art for NIR polymers with low band gaps that demonstrate overall charge neutrality, water solubility and functionality.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass or include one or more of the conventional technical aspects discussed herein.